Hello, I Had Intercourse When I Was On My Menstral

Hello, I had intercourse when I was on my menstral cycle, but at the end of it (where there was little to no blood) the condom broke. I'm not on the pill or any other contraceptives. I took 3 birth control pills from a friend (whom is heavier than I) and I took them right after I had had sex. But two weeks later I had blood in my underwear. What could this mean? Am I pregnant?